Fix missed renames in #22632 (#23688)

Fix a bug where a GPUI macro still used `ModelContext`
Rename `AsyncAppContext` -> `AsyncApp`
Rename update_model, read_model, insert_model, and reserve_model to
update_entity, read_entity, insert_entity, and reserve_entity

Release Notes:

- N/A

crates/languages/src/tailwind.rs

@@ -2,7 +2,7 @@ use anyhow::{anyhow, Result};
 use async_trait::async_trait;
 use collections::HashMap;
 use futures::StreamExt;
-use gpui::AsyncAppContext;
+use gpui::AsyncApp;
 use language::{LanguageToolchainStore, LspAdapter, LspAdapterDelegate};
 use lsp::{LanguageServerBinary, LanguageServerName};
 use node_runtime::NodeRuntime;
@@ -135,7 +135,7 @@ impl LspAdapter for TailwindLspAdapter {
         _: &dyn Fs,
         delegate: &Arc<dyn LspAdapterDelegate>,
         _: Arc<dyn LanguageToolchainStore>,
-        cx: &mut AsyncAppContext,
+        cx: &mut AsyncApp,
     ) -> Result<Value> {
         let mut tailwind_user_settings = cx.update(|cx| {
             language_server_settings(delegate.as_ref(), &Self::SERVER_NAME, cx)